HELP PLZ !! With a sick Starfish !!

I have had my Choc. chip starfish for just over 3 months now and he has been doing great i thought... This morning i woke up and noticed that where two of his arms meet is almost like it's "rotting"... The area im worried about is where his top right arm and bottom right arm meet, the area is whitish in color and really does not look good. PLZ help me find out what's wrong and how to fix it ! Also i don't know if this could be of any use but he sometimes goes up to the surface of the water and lets his arms go out of the water into the air ?!?
Water parameters are
Ammonia=0
Nitrite=0
Nitrate= 0 ppm - 5ppm never higher than 5ppm

It's not in a reef tank, just a FOWLR and a few other inverts... Someone just told me that these choc chip starfish "molt" and he should be fine. Anyone know if this is true ? I'm just concerned because if he needs treatment i want to go get it right away.

As far as I know there are no treatments for starfish when they are sick or wounded. Either he will heal or he will slowly melt away. Once they start to go they usually dont recover. Sorry but I'm guessing he will continue to decline. I would test your nitrates and have your sg checked with a refrac, Ive also noticed MOST stars dont like temps above 78. I wish you luck!

Just thought i would give an update on how the Choc. chip star is doing... It appears that he is healing and I'm almost certain that he did "molt". As I mentioned in an earlier post, someone I know, with a lifetime of experience told me that these specific type of sea stars "molt" and will return to normal after a short amount of time(1-2weeks) This appears true to me as well so I just wanted to get this information out there, to help other invertebrate keepers !